JPH0912644A - Clear heat-resistant resin - Google Patents

Abstract

PURPOSE: To obtain a resin which has good mechanical characteristics, low moisture absorption properties, and excellent heat resistance and clarity by copolymerizing a specific α-methylene-γ-butyrolactone deriv. and other photopolymerizable monomers. CONSTITUTION: A clear heat-resistant resin having a wt. average mol.wt. (in terms of polystyrene) by GPC of 10,000-300,000 is obtd. by copolymerizing 20-90wt.% at least one α-methylene-γ-butyrolactone deriv. (e.g. a-methylene-4- methyl-γ-butyrolactone) and 80-10wt.% monomer component e.g. comprising an arom. vinyl compd. (e.g. styrene or α-methylstyrene) and a vinyl monomer [e.g. (meth)acrylic acid or methyl (meth)acrylate] in the presence of a polymn. initiator at 50-150 deg.C.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent heat-resistant resin, and more specifically, it has excellent transparency and high heat resistance.
The present invention relates to a resin having good mechanical properties and excellent low hygroscopicity.

[0002]

2. Description of the Related Art Methacrylic resins containing methyl methacrylate as the main component and styrene resins containing styrene as the main component are transparent and have excellent weather resistance, mechanical strength and heat resistance. Since it has a relatively balanced performance in terms of physical properties and moldability, it is used in many applications such as signboards, lighting covers, nameplates, automobile parts, decorations and sundries.
However, the glass transition temperature (Tg) of these resins
Since methacrylic resin is around 110 ° C. and styrene resin is around 90 ° C., it is difficult to use in the field where heat resistance is required.

Therefore, in recent years, a heat-resistant resin obtained by copolymerizing methyl methacrylate or styrene with maleic acid, α-methylstyrene, maleimide or the like has been developed (Japanese Patent Publication Nos. 49-10156 and 43). −
9753, Japanese Patent Publication No. 2-46605, etc.). However, these heat-resistant resins have deteriorated optical properties, mechanical properties, weather resistance, etc. of the resin due to the copolymerization of maleic acid, α-methylstyrene or maleimide, and have not yet reached the point where sufficient heat resistance is obtained. .

As a resin having high heat resistance and transparency, Macromolecules, Vol. 12, p. 546 (1979).
, A homopolymer of α-methylene-γ-butyrolactone, and Polymer, Vol. 20, p. 1215 (1979).
(Year) describes a copolymer of α-methylene-γ-butyrolactone with methyl methacrylate, styrene and the like. However, these resins have drawbacks that they are low in mechanical strength when formed into molded articles and easily absorb water due to brittleness caused by a homopolymer of α-methylene-γ-butyrolactone.

[0005]

Means for Solving the Problems As a result of intensive investigations, the inventors of the present invention conducted a study to obtain a transparent resin having good mechanical properties, low hygroscopicity and excellent heat resistance. −
It was found that a resin obtained by copolymerizing a methylene-γ-butyrolactone derivative with a specific amount of another copolymerizable monomer can achieve the above object, and completed the present invention.

That is, the present invention is a transparent resin obtained by polymerizing a monomer (A) represented by the following general formula (I) and another polymerizable monomer (B) copolymerizable therewith. It is in heat resistant resin.

[0007]

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Monomer (A) used in the present invention
Is a derivative of α-methylene-γ-butyrolactone represented by the general formula (I). In the monomer (A) of the general formula (I), when the structure of the substituents of R ₁ and R ₂ becomes bulky, the polymerizability decreases, and the heat resistance of the resulting resin lowers. R ₁ other than _one hydrogen atom, R ₂
The substituent of is an alkyl group having 1 to 12 carbon atoms, or 1 to 12 carbon atoms.
12 is preferably a fluorine-containing alkyl group, a phenyl group or a cyclohexyl group. The alkyl group having 1 to 12 carbon atoms in R ₁ and R ₂ is C _n H _{2n + 1} (n is 1 to 1).
Is an integer of 2), and the shape thereof may be linear or branched. Also, carbon number 1
To 12 fluorine-containing alkyl groups are C _n F _m H _{2n + 1-m} (n
Is an integer of 1 to 12 and m is an integer of 2n + 1 or less), and even if the shape is linear,
It may be branched, and the number of fluorine atoms and the bonding position are not limited. Further, the phenyl group may be a lower alkylphenyl group substituted with a lower alkyl group.

Monomer (A) represented by the above general formula (I)
, For example, α-methylene-4-methyl-γ
-Butyrolactone, α-methylene-4-ethyl-γ-butyrolactone, α-methylene-4-t-butyl-γ-butyrolactone, α-methylene-4-undecyl-γ-butyrolactone, α-methylene-4,4-dimethyl −γ−
Butyrolactone, α-methylene-4-methyl-4-ethyl-γ-butyrolactone, α-methylene-4,4-diethyl-γ-butyrolactone, α-methylene-4,4-diisopropyl-γ-butyrolactone, α-methylene- Four
-Phenyl-γ-butyrolactone, α-methylene-4-
Phenyl-4-methyl-γ-butyrolactone, α-methylene-4,4-diphenyl-γ-butyrolactone, α-
Methylene-4-cyclohexyl-γ-butyrolactone,
α-methylene-4-trifluoromethyl-γ-butyrolactone, α-methylene-4-perfluoroethyl-γ-
Examples include butyrolactone and α-methylene-4,4-ditrifluoromethyl-γ-butyrolactone. These can be used alone or in combination of two or more.

The other polymerizable monomer (B) copolymerizable with the monomer (A) represented by the general formula (I) used in the present invention is a monomer of the general formula (I). Quantity (A)
It is not particularly limited as long as it can be copolymerized with styrene, α-methylstyrene, paramethylstyrene, isopropenylstyrene, aromatic vinyl compounds such as vinyltoluene, and vinyl-based compounds represented by the following general formula (II) Those selected from monomers are preferred.

[0011]

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Examples of the vinyl-based monomer represented by the general formula (II) include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, and (meth) acrylic acid. ) Butyl acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, trifluoromethyl (meth) acrylate, 2,2, (meth) acrylate
2 trifluoroethyl, 2,2 (meth) acrylic acid
3,4,4,4 hexafluorobutyl, 2,2,3,3,4,4,5,5 octafluoropentyl (meth) acrylate, 2- (perfluorooctyl) ethyl (meth) acrylate, α -Trifluoromethyl fluoroacrylate, α-fluoroacrylic acid 2,2,2 trifluoroethyl, α-fluoroacrylic acid 2,2,3,4,4,4
Hexafluorobutyl, α-fluoroacrylic acid 2,
2,3,3,4,4,5,5 octafluoropentyl,
α-fluoroacrylic acid 2- (perfluorooctyl)
Ethyl and the like. Among these monomers, it is preferable to use an aromatic vinyl compound. Further, these monomers can be used alone or in combination of two or more kinds.

In the vinyl type monomer represented by the general formula (II), if the structure of the substituent of R ₄ becomes bulky, the heat resistance of the obtained resin is lowered and the polymerizability is also hindered. Therefore, the alkyl group and the fluorine-containing alkyl group of R ₄ are the same as the alkyl group having 1 to 12 carbon atoms and the carbon number of 1 to 12 as the substituent of the monomer (A) represented by the general formula (I). Is preferably a fluorine-containing alkyl group.

The amount of the monomer (A) represented by the general formula (I) in the present invention is about 20 to 90 parts by weight based on 100 parts by weight of the monomer mixture consisting of the monomer (B). Is preferred. If the amount of the monomer (A) used is too small, sufficient heat resistance cannot be obtained, and if it is too large, the mechanical properties decrease and the water absorption increases. Preferably 30 to 7
0 parts by weight.

The polymerization method used in the present invention is not particularly limited, and examples thereof include bulk polymerization, solution polymerization, suspension polymerization and emulsion polymerization.

The polymerization initiator used is not particularly limited as long as it does not adversely affect side reactions or coloring during polymerization, and the polymerization mode, polymerization temperature, polymerization rate,
It can be arbitrarily selected depending on the polymerization time, and one kind can be used or two or more kinds can be used in combination. Examples of the polymerization initiator include, for example, 2,2-azobisisobutyronitrile,
Azo initiators such as 2,2′-azobis-2,4-dimethylvaleronitrile, benzoyl peroxide, di-t
-Butyl peroxide, organic peroxides such as dicumyl peroxide, photoinitiators such as benzoin methyl ether and benzophenone, sulfates such as ammonium persulfate,
Examples include sodium sulfite and redox initiators.

The chain transfer agent optionally used for controlling the molecular weight in the polymerization is not particularly limited as long as it does not adversely affect side reactions or coloring during the polymerization. The molecular weight can be arbitrarily selected, and one kind or a combination of two or more kinds can be used. Examples of the chain transfer agent include primary, secondary and tertiary mercaptans such as n-butyl mercaptan, isobutyl mercaptan, t-butyl mercaptan and octyl mercaptan, thioglycolic acid and its ester.

The polymerization temperature is not generally determined depending on the polymerization initiator used and the type of polymerization, but is 50 to 150.
It is preferably carried out in the range of ° C.

The transparent heat-resistant resin of the present invention is produced by the above-mentioned method. However, in view of quality and quality requirements, a plasticizer, a cross-linking agent, a heat stabilizer, a colorant, an ultraviolet absorber, a releasing agent may be added if necessary. A mold agent or the like can be added.

The molecular weight of the transparent heat-resistant resin of the present invention is not particularly limited, but if it is too high, the molding processability is lowered, and if it is too low, sufficient mechanical properties cannot be obtained. Therefore, the molecular weight determined by GPC polystyrene conversion is 10,0 in terms of weight average molecular weight.
The range of 00 to 300,000 is preferable.

[0021]

The present invention will be described in more detail with reference to the following examples. The evaluation of the physical properties used in Examples and Comparative Examples was performed by the methods described below. In addition, the part in an example shows a weight part.

(1) Glass transition temperature (° C.) Measured by DSC (differential scanning calorimeter).

(2) Total light transmittance (%) Measured in accordance with ASTM D1003.

(3) Haze value (%) Measured in accordance with ASTM D1003.

(4) Tensile elongation (%) Measured in accordance with ASTM D638.

(5) Water absorption rate (%) According to ASTM D570, it was measured by immersing in water at 23 ° C. for 24 hours.

[Example 1] 50% 37% formalin aqueous solution
Parts, 70 parts of methyl acrylate and 30 parts of 1,4-diazabicyclo- [2,2,2] -octane were dissolved in 200 parts of 1,2-dimethoxyethane and stirred at room temperature for 50 hours, and then the organic phase was removed from the reaction solution. Was separated to obtain methyl α-hydroxymethyl acrylate.

Next, this methyl α-hydroxymethyl acrylate was diluted with 6 volumes of anhydrous ether, 20 parts of phosphorus bromide was added dropwise in an ice bath, and the mixture was stirred at room temperature for 3 hours. After completion of the reaction, water was added and the organic phase was separated to obtain methyl α-bromomethyl acrylate.

Then, a solution prepared by diluting this methyl α-bromomethylacrylate with 3 times the amount of anhydrous tetrahydrofuran was added with 7 parts of zinc and 25 parts of acetone.
0 part of anhydrous tetrahydrofuran solution was added dropwise. After completion of the dropping, the mixture was stirred for 3 hours, poured into a 10% aqueous hydrochloric acid solution, the organic phase was washed well with water, dehydrated over sodium sulfate, and distilled under reduced pressure to obtain α-methylene-4,4-dimethyl-γ-butyrolactone. Was obtained (GLC purity 99% or more).

This α-methylene-4,4-dimethyl-γ
16 parts of butyrolactone, 24 parts of methyl methacrylate
Parts, di-t-butyl peroxide 0.004 parts and octyl mercaptan 0.048 parts, and the resulting mixture was placed in a glass ampoule and sealed under vacuum to give 1
The polymerization reaction was carried out for 24 hours in an oil bath at 50 ° C. After the polymerization, the content of the ampoule was dissolved in 400 parts of dimethylformamide and poured into methanol. Next, the precipitated polymer was separated and taken out, and vacuum dried at 100 ° C. for 48 hours to obtain a copolymer composed of α-methylene-4,4-dimethyl-γ-butyrolactone and methyl methacrylate. Then, the glass transition temperature of the obtained copolymer,
The total light transmittance, haze value, tensile elongation and water absorption were measured. In addition, the measurement of total light transmittance, haze value, tensile elongation, water absorption is
The test was performed using a plate-shaped test piece having a thickness of 2 mm obtained by hot pressing the copolymer at 245 ° C. Table 1 shows the results. The infrared absorption spectrum of the obtained copolymer is shown in FIG.

Example 2 As Example 1, except that α-methylene-4,4-dimethyl-γ-butyrolactone was synthesized and styrene was used instead of methyl methacrylate in Example 1. Similarly, α-methylene-
A copolymer of 4,4-dimethyl-γ-butyrolactone and styrene was obtained. Then, the glass transition temperature, total light transmittance, haze value, tensile elongation and water absorption of the obtained copolymer were measured in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 1 In 100 parts of anhydrous tetrahydrolane in which 10 parts of sodium ethoxide was dispersed,
After adding 25 parts of diethyl oxalate, γ-
15 parts of butyrolactone was added dropwise and left overnight. Formaldehyde was blown into the reaction solution, and the solvent was distilled off, followed by extraction with ether. This ether phase was mixed with saturated aqueous sodium carbonate solution and stirred for 1 hour. Then, the solvent was distilled off, and the residue was distilled under reduced pressure with a Vigreux tube attached to obtain α-methylene-γ-butyrolactone (GLC).
Purity 99% or more). Then, this α-methylene-γ-butyrolactone was copolymerized with methyl methacrylate in the same manner as in Example 1 to obtain a copolymer of α-methylene-γ-butyrolactone and methyl methacrylate. Then
The glass transition temperature, total light transmittance, haze value, tensile elongation, and water absorption of the obtained copolymer were measured in the same manner as in Example 1. Table 1 shows the results.

Comparative Example 2 α-methylene-γ-butyrolactone synthesized in the same manner as in Comparative Example 1 was used and copolymerized with styrene in the same manner as in Example 2 to obtain α-methylene-γ.
A copolymer of butyrolactone and styrene was obtained. Then, the glass transition temperature of the obtained copolymer,
The total light transmittance, haze value, tensile elongation and water absorption were measured in the same manner as in Example 1. Table 1 shows the results.

Example 3 Dimethyl malonate 3 at room temperature
Five parts were added dropwise to a methanol solution of 12.5% sodium methylate. Then, 16 parts of butylene oxide was added dropwise at 50 ° C., then the temperature was raised to 70 ° C. and the mixture was stirred for 3 hours.
After stirring, the mixture was cooled to 50 ° C., 50 parts of a 20% aqueous sodium hydroxide solution was added, and the mixture was allowed to cool to room temperature with stirring.
Methanol was distilled off from this solution under reduced pressure, 30% sulfuric acid was added to adjust the pH to 2, and the mixture was extracted 3 times with ethyl acetate. Then, 18 parts of diethylamine was added to the residue obtained by distilling off ethyl acetate under reduced pressure at 35 ° C., and 43 parts of 37% aqueous formalin solution was added dropwise at room temperature, followed by stirring overnight. The reaction solution was further stirred at 70 ° C. for 1 hour and then extracted with ethyl acetate. This organic phase was thoroughly washed with 10% sulfuric acid and water, and then distilled under reduced pressure. 0.02 parts of hydroquinone monomethyl ether was added to the resulting residue, which was then distilled under reduced pressure to obtain α-methylene-4-ethyl-γ-. Butyrolactone was synthesized.

Then, this α-methylene-4-ethyl-
γ-Butyrolactone was copolymerized with methyl methacrylate in the same manner as in Example 1 to obtain α-methylene-4-ethyl-γ-
A copolymer of butyrolactone and methyl methacrylate was obtained. Then, the glass transition temperature, total light transmittance, haze value, tensile elongation and water absorption of the obtained copolymer were measured in the same manner as in Example 1. Table 1 shows the results.

Example 4 Using α-methylene-4-ethyl-γ-butyrolactone synthesized in the same manner as in Example 3, it was copolymerized with styrene in the same manner as in Example 2 to obtain α-
A copolymer of methylene-4-ethyl-γ-butyrolactone and styrene was obtained. Then, the glass transition temperature, total light transmittance, haze value, tensile elongation and water absorption of the obtained copolymer were measured in the same manner as in Example 1. However,
The total light transmittance, haze value, tensile elongation, and water absorption were measured using a plate-shaped test piece having a thickness of 2 mm obtained by hot pressing the copolymer at 240 ° C. Table 1 shows the results.

[0037]

[Table 1]

[0038]

EFFECT OF THE INVENTION The transparent heat-resistant resin of the present invention has excellent transparency and high heat resistance, and has excellent mechanical properties and low hygroscopicity. Can be suitably used for applications requiring high heat resistance, such as automobile parts, optical device parts, industrial parts, household parts, etc.

[Brief description of the drawings]

FIG. 1 is an analysis diagram of an infrared absorption spectrum of the copolymer obtained in Example 1.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tetsuya Ikemoto 20-1 Miyuki-cho, Otake-shi, Hiroshima Mitsubishi Rayon Co., Ltd. Central Research Laboratory (72) Inventor Keiichi Sakashita 2-3-19 Kyobashi, Chuo-ku, Tokyo Within Mitsubishi Rayon Co., Ltd.

Claims (3)

[Claims] 1. A monomer (A) represented by the following general formula (I) and another polymerizable monomer (B) copolymerizable therewith:
A transparent heat-resistant resin obtained by polymerizing and. Embedded image 2. The transparent heat-resistant resin according to claim 1, wherein the other copolymerizable polymerizable monomer (B) is an aromatic vinyl compound. 3. The transparent heat resistant resin according to claim 1, wherein the other copolymerizable polymerizable monomer (B) is a vinyl monomer represented by the following general formula (II). . Embedded image